Srivastava K D, Magazine H I
Department of Biology, Queens College and Graduate School, City University of New York, Flushing 11367, USA.
J Immunol. 1998 Nov 1;161(9):5039-44.
The effect of thrombin receptor activation on monocyte conformation was evaluated using the human monocyte cell line, THP-1, and the thrombin mimetic peptide, Trap-14. Treatment of THP-1 cells with Trap-14 induced rapid rounding of ameboid cells adherent to fibronectin-coated slides, whereas cell rounding was abrogated in the presence of the nitric oxide synthase inhibitor, NG-nitro-L-arginine or the endothelin B receptor antagonist, BQ-788. Endothelin-1 (ET-1) levels in the culture supernatant increased markedly within minutes of Trap-14 exposure with a concomitant loss in cellular ET-1 immunoreactivity. Importantly, loss of ET-1 immunoreactivity was blocked by pretreatment with the vesicle translocation inhibitor, nocodazole. Trap-14 potently induced the release of NO from THP-1 cells, whereas NO release was ablated by preincubation with BQ-788. These data demonstrate that thrombin receptor activation may inhibit cellular spreading as a result of autocrine ET-1 release and subsequent endothelin B receptor-dependent NO production, and suggest that initial exposure of inflammatory cells to thrombin may limit cellular activation and recruitment.
使用人单核细胞系THP - 1和凝血酶模拟肽Trap - 14评估凝血酶受体激活对单核细胞形态的影响。用Trap - 14处理THP - 1细胞可诱导粘附于纤连蛋白包被载玻片上的阿米巴样细胞迅速变圆，而在一氧化氮合酶抑制剂NG - 硝基 - L - 精氨酸或内皮素B受体拮抗剂BQ - 788存在的情况下，细胞变圆现象消失。在Trap - 14暴露数分钟内，培养上清液中的内皮素 - 1（ET - 1）水平显著升高，同时细胞内ET - 1免疫反应性丧失。重要的是，用囊泡转运抑制剂诺考达唑预处理可阻断ET - 1免疫反应性的丧失。Trap - 14能有效诱导THP - 1细胞释放NO，而与BQ - 788预孵育可消除NO释放。这些数据表明，凝血酶受体激活可能由于自分泌ET - 1释放及随后内皮素B受体依赖性NO产生而抑制细胞铺展，并提示炎性细胞最初接触凝血酶可能会限制细胞活化和募集。
